1. Technical Field
The present invention relates to a document reading apparatus for determining a position of a carriage that reciprocates in a predetermined range along a predetermined direction and a method of determining a position of a carriage.
2. Related Art
Various image reading devices such as an image scanner include an image reading sensor such as an image sensor to read an image from a document. The image reading sensor is disposed in a so-called carriage that moves relative to the document. At the time of reading an image from a document, the image reading sensor reads an image from a document while moving relative to the document along with the carriage. Here, the carriage mounted with the image reading sensor starts its movement from a predetermined reference position called a home position (HP), moves relative to the document, and performs an operation of reading an image of the document by the use of the image reading sensor. In the related art, a home position sensor is provided to detect whether the carriage is located at the home position (HP) (see JP-A-2006-10718).
However, to provide the home position sensor causes an increase in the number of components and an increase in cost. Accordingly, without using the home position sensor, it is necessary to locate the carriage mounted with the image reading sensor at the home position at the time of reading an image from a document.